In the field of this invention it is known that enhanced function storage subsystems (e.g., for a system of one or more disk drives) contain many logical resources. These resources can be managed by a storage adapter or controller. In this context, a logical resource is an entity which exposes a disk-like behaviour but which may have properties not ordinarily associated with individual disk drives. These properties include enhanced performance, reliability, availability and data transformation operations such as flash copy. There may be a complex many-to-many relationship between logical resources and other logical resources or physical resources. For example a RAID-5 (Redundant Array of Independent Disks) arrangement contains usually between 4 and 16 component disks. Data is striped across the components and a parity check is calculated and stored. The attributes of, and relationships between, these logical resources must be gathered and manipulated by software products to allow users to maintain their subsystem. Since the primary purpose of such a storage subsystem is to perform Input/Output (IO) operations from operating system to disk drive(s)—IO has priority. This may be at the expense of user transactions that are sent to the subsystem in order to generate the details of the logical resources available in the subsystem. This in turn can result in very slow user response times—especially when the subsystem is under heavy IO load.
It is known to provide a cache of subsystem configuration data. This provides a centralized point of reference for user information relating to the subsystem. It is known from U.S. Pat. No. 5,895,493 that such a system will gather information from various systems and provide a point for the user to access and obtain information about a group of systems.
However, this approach has the disadvantage(s) that the system of the referenced patent does not describe how this data is updated. It relies on the subsystems notifying the main cache of changes and updates and passing the data.
A need therefore exists for an arrangement and method of updating storage subsystem cache data wherein the abovementioned disadvantage(s) may be alleviated.